GP477R Engineering Installation

3.2 Wiring steps for power terminals

Power off confirmation: Before connecting any wires, make sure that the power cord is completely disconnected from the power supply network and the circuit breaker is in the OFF position.

Open the terminal cover: Use a Phillips screwdriver to unscrew the protective cover on the power input terminal block.

Terminal definition: The terminal block has three markings:

L: AC100V live line

N: AC100V neutral wire

FG: Grounding terminal (connected to GP casing)

Use circular terminals with insulated sleeves: To prevent short circuits caused by loose screws, it is recommended to use JST V2-MS3 or equivalent circular cold pressed terminals with insulated sleeves. The maximum cross-sectional area of the wire is 2mm ² (approximately 14AWG).

Wiring: Loosen the corresponding screw, insert the wire with the pressed terminal and tighten it again, with a torque of 0.5-0.6 N · m.

Grounding: The FG terminal must be directly connected to the grounding copper bar of the control cabinet using a separate wire, and the grounding resistance should be less than 100 Ω. It is prohibited to short-circuit FG and N lines, nor to suspend them, otherwise the anti-interference ability of GP will sharply decrease.

3.3 Anti interference measures for power supply

It is recommended to parallel a surge absorber (varistor) at the power input end to suppress spikes caused by lightning strikes or inductive load switching.

If the factory power grid has severe noise (such as a large number of frequency converters), an isolation transformer or noise filtering transformer should be installed at the front end of the GP power supply.

The power cord should be as short as possible and routed separately from the power and motor lines to avoid bundling in the same cable tray.

Twisting the power cord into a twisted pair before connecting it to the terminal can further improve the common mode noise suppression capability.

Serial interface (RS-232C/RS-422)

The GP477R is equipped with a 25 pin D-sub female socket (located on the back of the body) that can be configured in RS-232C or RS-422 mode for connecting PLCs, computers, or other master station equipment. This interface supports full duplex communication, with a maximum baud rate typically reaching 115.2kbps (depending on the system program version).

4.1 Pin Allocation Table

Pin signal name description Pin signal name description

1 FG frame grounding 14 VCC+5V ± 5% output 0.25A

2 SD sends data (RS-232C) 15 SDB sends data B (RS-422)

3 RD receives data (RS-232C) 16 RDB receives data B (RS-422)

4 RS request sent (RS-232C) 17 NC not connected

5 CS clear send (RS-232C) 18 CSB clear send B (RS-422)

6 NC-19 ERB allows reception of B (RS-422)

7 SG signal grounded 20 ER allows reception (RS-232C)

8 CD Carrier Detection (RS-232C) 21 CSA Clear Transmission A (RS-422)

9 TRMX terminal resistor (RS-422) 22 ERA allows receiving A (RS-422)

10 RDA Received Data A (RS-422) 23 Reserved

11 SDA sends data A (RS-422) 24 NC not connected

12 NC-25 Reserved

13 NC - 

Important precautions:

Pin 14 (VCC) can output a+5V/0.25A power supply to external converters or low-power devices. This output has no overload protection, and it must be ensured that the total current does not exceed the rated value during use, otherwise it will damage the internal power circuit of the GP.

In RS-422 mode, pin 9 (TRMX) is required to connect the terminal resistor. When GP is located at the end of the bus, TRMX should be short circuited to RDA (pin 10); The specific short-circuit method depends on the communication protocol, and it is generally recommended to connect only the two end devices to a 120 Ω resistor when connecting multiple points.

The signal ground (pin 7 SG) must be connected to the signal ground of the opposite device, otherwise it may cause common mode voltage damage to the interface chip.

4.2 Recommended connectors and cables

Connector: OMRON XM2A-501 (25 pin male) with threaded locking.

Shell: OMRON XM2S-2511, with matching screws of M2.6 × 0.45 coarse teeth.

Cable: Hitachi cable CO-MA-VV-SB5P × 28AWG or other twisted pair shielded cable (at least 5 pairs of wires) is recommended. RS-232C can use standard direct serial cable, while RS-422 requires twisted pair transmission of differential signals.

4.3 Typical Wiring Examples

RS-232C three wire system (communicating with PC serial port): GP's SD (2) → PC's RD, GP's RD (3) → PC's SD, GP's SG (7) → PC's SG. If hardware handshake is required, GP's RS (4) and CS (5) can be connected to the corresponding signal of the PC, but most applications only require three wires.

RS-422 four wire system (communicating with PLC): SDA of GP (11) → RDA of PLC, SDB of GP (15) → RDB of PLC, RDA of GP (10) → SDA of PLC, RDB of GP (16) → SDB of PLC, while connecting SG (7) of GP to SG of PLC.

Printer interface

The GP477R also has a 14 pin flat interface on the back (Centronics compatible) for connecting to parallel printers to print alarm records or hard copy screens. The interface adopts Fujitsu FCN-787P014-G/R connector.

Pin Function Summary (Based on Original Document Inference):

Standard parallel port signals such as data cable STB, D0-D7, BUSY, etc.