CAREL PGD Handheld Operator Configuration Replacement

4.2 “NO LINK”

Phenomenon: The display screen continues to show "NO LINK" without any other information.

Reason: The handheld device did not receive any signal from the PLAN network. Possible reasons include:

RJ12 cable disconnected or short circuited.

The address setting of the handheld device is incorrect (for example, set to 0 but there are multiple nodes in the network).

The entire PLAN network has no main station or all PCOs are not powered on.

Solution:

Check if the communication cables are intact, and use a multimeter to measure the continuity of each core (RJ12 pin definition: usually corresponding to 1-6, please refer to the PCO manual for details).

Confirm that at least one PCO motherboard has been powered on and is in operation.

Enter the configuration mode of the handheld device and check if the address conflicts with other devices in the network (the address must be unique).

If there is only one PCO in the network, setting the controller address to 0 (point-to-point mode) can simplify communication.

4.3 The screen backlight does not light up but the display is normal

Reason: The backlight LED is aging or the backlight setting is turned off.

Solution:

For white backlight models, the backlight is usually on by default. The backlight switch can be adjusted by long pressing a combination key (as defined in the application software).

If the backlight still does not light up, it may be due to damage to the internal LED and the handheld device needs to be replaced.

4.4 Button unresponsive or slow response

Reason: After long-term use, the conductive rubber may age, become waterlogged, or accumulate dust.

Solution:

After power off, remove the front panel of the manipulator and clean the conductive rubber and PCB contacts with anhydrous alcohol.

If the conductive rubber has hardened, you can try using a 2B pencil to temporarily improve the contact points, but it is recommended to replace the handheld device.

The complete process of replacing old PCO/PCOT terminals with PGD

Many devices on site are still using early PCO/PCOT text controllers (such as PCOT00, PCOO series). When these terminals malfunction or need to be upgraded, replace them with PGD according to the following steps:

5.1 Preparation work

Record the original controller address: View its PLAN address in the original controller configuration menu (usually displayed on the boot screen or parameter list). If unable to view, you can temporarily use PGD to scan the network.

Confirm PCO model and firmware: PGD is compatible with mainstream models such as PCO *, PCOe, PCO3, etc., but it is recommended to confirm that the firmware version of PCO supports graphic display (generally supported by firmware after 2005).

Purchase matching PGD models: If the original handheld device displays single line text and only basic parameters need to be viewed, PGD0000N00 is sufficient; If you need to display a trend chart or more information, select PGD1000N00/W0.

5.2 Physical replacement steps

Power off: Disconnect the power supply of the PCO motherboard to avoid damaging the interface during live plugging and unplugging.

Dismantle the old handheld device: Remove the old terminal panel, unplug the RJ12 plug and flat cable (if any).

Installation of PGD: Adjust the installation holes according to the opening requirements in Part 2 (note that PGD0 and PGD1 have different sizes), and use adapter plates if necessary. Embed and secure the PGD panel.

Connecting cable: Insert the RJ12 cable into the interface behind the PGD (with no polarity direction, but it needs to be fully inserted). If the old system has a flat cable, insert it into the D interface of PGD (note pin1 alignment).

Set Address: After powering on, enter configuration mode and set the PGD address to the same value as the original controller. If the original address is unknown, it can be temporarily set to 1 and then queried on the PCO end.

Test communication: Observe whether PGD displays PCO menus and variables normally. If 'NO LINK' is displayed, check the address and cable.

5.3 Adjust the PCO side association list (if necessary)

If PGD has set the correct address but still cannot communicate, it may be due to PCO's "controller list" restricting access. At this point, it is necessary to connect to PCO programming tools (such as c.design or pCOSoft), find the "Terminal list" parameter, and add the address of PGD to the shared or dedicated list. Alternatively, set the list to "Allow All" (value 0).

5.4 Functional Verification

Test each button one by one to confirm that the functions of page up and down, numerical modification, confirmation, and exit are normal.

Check if the graphical interface is displaying as expected (PCO application software may need to support graphics, otherwise it will still be displayed as text).

Simulate alarms (such as disconnecting sensors) and verify whether the alarm information can be displayed correctly.

Summary of Application Scenarios and Advantages

6.1 Typical Application Scenarios

Refrigeration unit: Replace aging PCO terminals, display evaporator temperature, condensing pressure, compressor status, etc. graphically.