Product Overview and Positioning
Lauer PCS 950 is a modular programmable control console designed specifically for human-machine interaction in industrial automation. It provides 20 freely definable function keys (F1-F20), each key is equipped with a green and a yellow LED (a total of 40 LEDs), and a 320 × 240 pixel graphic LCD display screen (24 lines × 40 characters). This device supports up to 1024 messages (information/warning/fault level three priority), 255 configuration blocks, 8 timers (each with 8 cams), real-time clock, running hour counter, and comprehensive log printing function. Its core advantage lies in the saying 'today is like this, tomorrow is like this' - the same hardware can handle thousands of operating scenarios through different parameter configurations, without the need for extensive I/O wiring. PCS 950c is a color version, and PCS 950e is an explosion-proof type (used in hazardous areas). This article is based on the official technical manual, systematically sorting out its installation wiring, data word definitions, variable types, priority management, and troubleshooting points, helping engineers quickly master this powerful tool.
Hardware installation and electrical connection
2.1 Power Supply and Grounding
PCS 950 requires 24V DC ± 20% power supply, polarity reverse protection, with a typical power consumption of about 800mA (up to 1A at 19V). The power terminal is screw type, allowing a wire diameter of 2mm ². The protective conductor (PE) is isolated from 0V inside the equipment, and the PE is connected to the outer shell and shielding layer. To achieve optimal noise resistance, the casing must be grounded, with a grounding wire (4mm ²) as short as possible, and 0V should be grounded nearby on the power side (according to VDE standards). The rear of the device is equipped with a 10 bit DIL switch for driving selection, baud rate (PCSPROW transmission: ON=115.2k, OFF=38.4k), run/stop mode (DIL8: OFF for normal operation), and Flash write protection (DIL9/10: ON allows writing, OFF write protection). During operation, it is essential to ensure that DIL8 is turned off, otherwise it may cause abnormalities.
2.2 Interface and Communication
PCS 950 provides multiple serial interfaces:
PRO/COM: 25 pin Sub-D, configurable as RS232 or TTY (current loop).
COM: 15 pin Sub-D, can be configured as RS485 or RS422.
PRN: Another RS232/TTY interface used for printers.
The communication protocol is related to the PLC type and requires the use of corresponding drivers (such as Siemens S5 L1/AS511). DIL5/6 is used to select one of four configurations (such as baud rate, interface type). Configure cable PCS 733 for parameter download between PC and PCS.
2.3 Mechanical Installation
The opening size of the front panel is 204+1mm (width) × 259+1mm (height), with an installation depth of 65mm (excluding connectors) and a weight of approximately 2kg. The protection level of the front panel is IP65, and the rear is IP20. During installation, it is necessary to ensure that the sealing ring is correctly positioned to maintain IP65. Leave at least 100mm of heat dissipation space around.
Memory structure and data record management
The PCS 950 contains multiple types of internal storage devices:
EPROM (BIOS): Fixed boot program and display/keyboard drivers.
EEPROM: 2x8KB, used for Recipe Manager.
Flash EEPROM: 256KB firmware+2 × 128KB data recording+2 × 8KB driver. Data records (including variables, text, messages, etc.) are created and written using PCSPROW software.
Additional card slot: Can insert memory cards (Flash EEPROM) such as PCS 802/803/806 for storing additional data records or backups.
Battery backup RAM: 2 × 128KB, used for non-volatile data (logs, printer cache, etc.).
The device supports two internal data records (Record 1 and Record 2) and an external card slot data record (Record 3). At startup, you can select which one to load through the BIOS menu. Data records are generated by PCSPROW and can be transmitted together with firmware and drivers. Please note that only PCSPROW software can be used to create data records, other tools may cause malfunctions.
Core functions and parameterization
4.1 Variable System
PCS 950 supports rich variable formats for displaying and modifying data in PLC. Variables are divided into external variables (PLC data area, W110~W255) and internal variables (83 predefined system variables, such as message count, time, date, running hours, etc.).
External variable formats include:
BIT: Single bit, associated with two strings (such as "close/open").
STRING: One byte (0~255) corresponds to up to 256 strings (such as "automatic/manual/maintenance").
CSTRING: Similar to STRING, but immediately writes to PLC after modification (no need to press Enter).
BCD-1/2:1~8-bit BCD value (with leading zero option available).
BIN-1/2, VBIN-1/2:16/32-bit binary, supports calculator style input or shift input, can have symbols, decimal points, and scaling.
WORD: Display 16 bit words in binary, hexadecimal, or double decimal format.
ASCII: A string of up to 32 characters.
TIMER: 3-digit BCD time value+time base (0-3).
Variables can be used in text (idle page, operation page, message page), with a maximum of 8 variables per line. The actual value (ACTUAL) is read-only, while the preset value (PRESSET) and preset P-value (PRESSET-P) can be modified on the operation page. PRESSET-P is password protected (bit 7 controls editability).
4.2 Text and Page
The system includes the following text types:
Idle text (0~127): Displayed when there is no operation.
Operation Text (1-127): Operation page, which can include variable editing.
Message text (0~1023): associated with message bits, divided into three levels: information, warning, and fault.
Historical text: stored in the history buffer.
Printer Text: Message Printer and Operation Printer.
Help text: Press the<HLP>key to display, up to 32 lines.
The status page (upper area) and soft key row (lower area) can be defined separately and selected through W35. The middle area of the operation page displays the content corresponding to the current priority.
4.3 Priority Management
The system has 8 priorities (0~8), and only one is displayed at a time, but multiple priorities can be activated simultaneously. Priority from low to high:
Idle priority (display idle text)
Operation priority (operation page)
Information priority (information message)
Warning priority (warning message)
Fault priority (fault message)
Historical priority (historical display)
Recipe Manager (Reserved)
Communication error priority (automatically triggered)
Offline menu (enter by pressing HELP+CLR)
PLC can suppress (prohibit display) a certain priority through bits 8-11 of command word W36. For example, message interruptions can be temporarily suppressed while the operation page is being edited. The highest priority activated and not suppressed obtains display rights. The currently displayed priority number is fed back to the PLC in bits 12-15 of W17.
4.4 Messages and Logs
The message is triggered by the PLC setting message area (W41~W104, a total of 1024 bits). Each message can be assigned priority (information/warning/fault) and deletion mode (1-5):
PLC deletion: Reset the bit and it will disappear.
Manual deletion+reset bit: Press CLR to clear, and the PLC bit is reset at the same time.
Manual deletion (no reset bit): Press CLR to clear only the display, PLC bit needs to be reset separately.
Can only be deleted when the bit is 0: CLR is only valid when the PLC bit has been reset.
Confirmed deletion: The message flashes, stops flashing by pressing CLR, and is only deleted after the bit is reset.
Record the time of arrival, departure, and confirmation when a message enters, and store it in the history buffer (128 records) and the message printer buffer (1024 records). PLC can control printing tasks and pointer adjustments through W39. The history display is activated through W36 bit 1 and can be viewed by scrolling.
4.5 Timer and Running Hours
8 timers (W13 bits 0-7 feedback status), each with 8 cams (switch time pairs), can set the daily cycle ON/OFF time (hours, minutes, seconds). If the ON time is equal to the OFF time, it will be disabled; If ON<OFF, it is valid within the day; If ON>OFF, it is valid across midnight. The timer parameters can be modified online on the operation page.
The running hour counter (internal variable BETR_SD_iST) only runs when communication is established and W36 bit 2 is set to 1. It is stored in non-volatile RAM and can be preset.

Detailed explanation of data word communication
PCS and PLC exchange information through up to 256 data words (W0~W255). Different drivers may adjust the specific layout, but the general structure is as follows:
5.1 System Area (W0~W3)
W0~W2: Internally reserved for driving.
W3: Communication error word (see driver manual for specific meaning).
5.2 Status Area (PCS → PLC, W4~W19)
W4~W5: Press the key positions (F1~F20, control keys, numeric keys, etc.). When the button is pressed, the corresponding position is 1.
W9~W12: Time and date (year, month, day, week, hour, minute, second, BCD format).
W13~W17: PCS status. W13 bits 0-7 represent the timer status; Bit 11 indicates whether there are messages in the historical buffer; Bit 12 represents the historical clearing response; W14/W15 are printer old/new message counts; W16 is the activated priority bitmap; W17 is the current display priority number and text number.
W18~W19: preset value status. The high byte of W18 is the address of the newly modified preset value, and the low byte is the number of bytes written (0 represents the BIT variable, 2 represents 16 bits, 4 represents 32 bits); W19 is a bit mask (used for BIT variables to indicate which bit has been modified).
5.3 Command Area (PLC → PCS, W20~W40)
W20~W27: LED control. The green and yellow LEDs of each key are controlled by two bits to indicate their status (OFF, ON, flashing, reverse flashing). W20 green, W21 green flashing, W22 yellow, W23 yellow flashing (F1~F10); W24~W27 correspond to F11~F20.
W34: Work area bitmap number (bit 7=1 to enable dynamic switching).
W35: Status page number (high byte) and soft key line number (low byte).
W36 (Command Word A): Priority enable/suppress bit (bits 8-11 respectively suppress operation/information/warning/fault); Bit 12 allows for historical display; Enable offline menu for position 15; Position 3 allows alarm relay; Bit 2 starts running hour counter; Bit 0 synchronous clock (write 1 to trigger one-time synchronization).
W37 (Command Word B): bits 0-7 control message block transmission enable; Suppress the arrow LED in the operation page/help/message for bits 8-10 respectively; Disable buzzer at position 11; Clear the historical buffer (rising edge) at position 12; Set the printing direction at position 13 (1=last in first out, 0=first in first out); Bit 14 prohibits message printer logs; Stop printing task at position 15.
W38 (Command Word C): The high byte represents the idle text number (0-127) and the flashing bit; The low byte is the operation page number (1-127) and the PRESET-P editable bit (bit 7).
W39 (Command Word D): Message printer control. Positive numbers (1~32767) represent the number of prints; Negative numbers (-1~-32767) indicate printer pointer adjustment; -32768 Clears the printer buffer.
W40 (Command Word E): Operate the printer text number (non-zero trigger printing).
5.4 Message Area (W41~W110)
W41~W104 consist of 64 words, each with 16 bits, totaling 1024 message bits. Each message bit corresponds to a message text (0~1023). W105~W109 are reserved areas for expansion.
5.5 Variable Area (W110~W255)
Used to store external variables (actual value/preset value). The variable format is defined in PCSPROW, and the starting address can be freely assigned.
Configuration tool PCSPROW and typical debugging process
6.1 PCSPROW Software
PCSPROW is the only authorized parameterization software used for creating data records. It integrates a text editor, variable definition, message configuration, priority settings, printer formatting, and more. The generated data records (. FRM files) along with firmware and drivers are downloaded to the device via PCS 733 cable. Attention: Only PCSPROW can be used, other software may cause malfunctions.
6.2 Debugging steps
Hardware preparation: Confirm power supply of 24V, DIL8=OFF (running), DIL9/10=OFF (write protection temporarily set to ON during programming), connect programming cable PCS 733 to PC serial port.
PCSPROW configuration: Create a new project, define PLC drivers (such as Siemens S5-AS511), and set communication parameters (such as baud rate). Create an operation page, place variables, assign message bits and text, set priorities and deletion modes.
Download: Set DIL9/10 to ON and start PCSPROW transmission. Successfully set OFF to prevent accidental writing.
Run test: Restart PCS and observe SYS LED and COM LED. If COM flashes, it indicates that communication has not been established. Check the wiring and driver settings. Press HELP+CLR to enter the offline menu (requires W36 bit 15=1).
Online monitoring: Monitor keywords such as W16, W17, W36 through PLC program to confirm priority switching and message response.
6.3 Common Problems and Solutions
Communication cannot be established: Check whether the DIL5/6 configuration is consistent with the driver, whether the cable is correct (PCS 733), and the PLC side interface settings.
Message not displayed: Confirm that the text corresponding to the message bit has been created and the priority has not been suppressed (W36 bits 8-11).
The preset value cannot be modified: check W38 bit 7 (PRESET-P editable) and password level (operation page access level).
The history buffer is empty: Confirm that the message is configured with a log attribute (set in PCSPROW) and that the W36 bit 1 is 1.
Printer not working: Check PRN interface parameters (internal variables Z027~Z031), as well as XON/XOFF or RTS/CTS flow control settings.
LED not lit: Confirm that W20~W27 are correctly assigned values and that W36 bit 4 does not suppress LED transmission.
Advanced features and engineering considerations
7.1 Password Protection and Access Levels
10 password levels (0~9) can be set, with level 0 being open by default. Each operation page can specify the required level. Call the password input dialog box through the soft key function 256 (LOGIN), enter the correct password to activate the corresponding level; Soft key 257 (LOGOUT) returns to level 0. Passwords are stored in non-volatile RAM.
7.2 Printer Control Details
PCS 950 supports XON/XOFF (TTY/RS232) and RTS/CTS (RS232 only) flow control. Printer text can contain formatting control characters (such as page changes, line breaks, etc.), which can be customized through internal variables Z076~Z083. The printing direction and pointer adjustment of the message printer buffer are flexibly controlled through W39.
7.3 Running hour counter and clock synchronization
The running hour counter can preset an initial value and maintain the count even when communication is interrupted (as long as W36 bit 2 is 1). The clock synchronization function allows the PLC to write its own RTC value to the PCS (triggering one-time synchronization by setting W36 bit 0=1), or write the PCS clock value to the PLC (W9~W12).
7.4 Explosion proof model PCS 950e
The front panel of PCS 950e is intrinsically safe (EEx ib IIC T4) and is used for hazardous area 1/2. It displays as a 240 × 128 pixel LCD (instead of the standard 320 × 240) and is connected to the ENT-DC-1.1-950 control unit in the non hazardous area via an intrinsic safety data cable DATL-A7-4. All software functions are completely consistent with the standard model.
7.5 Maintenance Tips
The front panel is made of polyester film, and only a damp cloth is used for cleaning to prevent static electricity (especially in explosion-proof situations).
The backup battery for the internal RAM (model PCS 010) should be replaced every 5 years, and the device should be powered on during replacement to avoid losing log data.
During firmware upgrade, the runtime counter may be reset to zero and needs to be recalibrated through the internal variable BETR_SD_SOLL.
