Omron CPM2B Board PLC Practical Guide

Link area LR00~LR15 256 point 1:1 PLC Link sharing

Timer/Counter TIM/CNT 000~255 256 timers and counters

DM area DM0000~DM2047 2048 word data storage, power off maintenance

Read only DM DM6144~DM6599 456 words, user cannot write (set through programming device)

PLC Setup DM6600~DM6655 56 Word System Parameters

Important signs:

SR25211: Forced state hold bit (maintains forced set/reset state when switching modes when ON)

SR25212: I/O hold bit (keeps IR/LR state when ON starts/stops)

SR25214: Error log reset bit (clears logs when ON)

SR25308: Battery error flag (low battery voltage when turned on)

SR25309: Scan Time Exceeding Limit Flag

SR25500~SR25502: 0.1 seconds/0.2 seconds/1 second clock pulse

SR25503~SR25507: ER, CY, GR, EQ, LE logos

4.2 PLC Setup Key Settings

PLC Setup is modified in Program mode, and some parameters need to be restarted or rerun to take effect.

Typical settings for character function

Set the DM6600 startup mode to 0200 → GRAM, 0201 → MONITOR, 0202 → RUN

DM6601 can maintain the IOM Hold bit state by setting bit08~11 to 1

DM6602 program writing protection/extension instruction allocation bit08~11=1 allows users to allocate extension instructions

DM6618 maximum cycle time monitoring is set to 01~99 x units (10ms/100ms/1s)

DM6628 interrupt input enable setting every 2 bits: 0=normal input, 1=interrupt input, 2=fast response

DM6642 high-speed counter mode bit00~03:0=differential phase, 1=pulse+direction, 2=increase/decrease pulse, 4=increment; Bit08~15:01=high-speed counter, 02~04=synchronous pulse control

DM6645 RS-232C communication mode bit12~15:0=Host Link, 1=no protocol, 2=1:1 slave, 3=1:1 master, 4=NT Link

DM6655 Error Log/Low Battery Detection Left=0 Enable Low Battery Error

Key points for programming pulse output and high-speed counter

5.1 Pulse output (transistor models only)

Single phase no acceleration/deceleration: Use PULS (65) to set the pulse number, SPED (64) to set the frequency and start.

Variable duty cycle: using PWM (-) command, frequency 0.1-999.9Hz, duty cycle 0-100%.

Trapezoidal acceleration and deceleration: Using the ACC (-) command, the target frequency, acceleration and deceleration rate, and pulse count can be set.

Synchronous pulse control: Use the SYNC (-) command to multiply the input pulse of the high-speed counter by a coefficient and output it.

Notes:

Pulse output occupies OUT01000 and OUT01001. When used as a pulse output, the load current must be ≥ 10mA, otherwise the turn off response time will be too long, affecting the pulse waveform. If the load current is less than 10mA, parallel resistors (such as 1k Ω~2k Ω) should be used to pull the current.

The pulse output PV is stored in SR228~SR231 (32-bit signed numbers). Can be read using PRV (62).

5.2 High speed counter

The high-speed counter input occupies IN00000~IN00002. Set the mode through DM6642:

Differential phase (5kHz): A-phase IN00000, B-phase IN00001, Z-phase IN00002 (reset)

Pulse+direction (20kHz): IN00000 pulse, IN00001 direction

Increase/decrease pulse (20kHz): IN00000 increases, IN00001 decreases

Incremental mode (20kHz): IN00000 pulse

The counter PV is stored in SR248~SR249 (32-bit signed numbers). CTBL (63) can be used to load a comparison table (up to 8 ranges). When PV enters the set range, the corresponding AR1100~AR1107 flag bits are turned on or an interrupt is triggered. INI (61) can also be used for mode control and PV reset.

Hardware reset: In differential phase mode, IN00002 can be set as the Z-phase reset input (rising edge clears PV). If software reset is required, use the INI command.

Common fault diagnosis and troubleshooting

6.1 Meaning of LED indicator lights

Meaning of LED status

PWR (green) is turned off, there is no power supply or internal fault

RUN (green) extinguishes Program mode or fatal error

ERR (red) constantly on fatal error (PLC stopped)

ERR (red) flashing non fatal error (PLC continues to run)

PERI (orange) flashing peripheral port data transfer

COMM (orange) flashing RS-232C port data transmission

6.2 Common Non fatal Errors (ERR Flashing)

Reasons for Errors and Countermeasures

Battery error (no information) SR25308 ON. Low battery voltage, replace C500-BAT08 within one week

Scan time exceeds limit (F8) cycle time>100ms. Reduce scan time or modify DM6618 settings

PLC Setup error (9B) AR1300~1302 indicates specific errors. Check the settings of DM6600~DM6655

6.3 Fatal Error (ERR constantly on, RUN off)

Countermeasures for the meaning of error codes

Power outage (no information) Power interruption>2ms Check power cord and voltage

F1 (memory error) AR1308~1314 indicates the specific error checking program, read-only DM, and PLC setup. If the flash memory fails, replace the CPU board

F0 (without END instruction) program ends without END (01) plus END

C0 (I/O bus error) Communication fault between CPU board and expansion board Check expansion cable connection

E1 (too many I/O units) expansion board exceeds the limit and reduces the number of expansion boards

9F (cycle time exceeds monitoring value) actual scanning time>DM6618 set to adjust monitoring time or optimize program

6.4 Power Inspection Flowchart

Measure the power terminal voltage of the CPU board: 24V type should be above 20.4V; The 12V type should be above 10.8V.