Digital Gauges: Frequently Asked Questions

Question number FAQ-0066

DG-4240 Rear panel terminal block, signal wire connection

This section explains the signal connections on the rear panel.

Power cable connection.bmp (108044 bytes)

DG4240-29.gif (20001 bytes)

(1) Connecting to the cable

The terminal block uses M3.5 screws. We recommend using round crimp terminals that are compatible with these screws.

(2) Grounding

For safety and noise reduction, be sure to ground the grounding terminal (no. 3). Use a single-point grounding at the grounding terminal; do not use connecting wires.

Grounding type: 3rd class grounding or higher (100Ω or less)
Grounding wire: Soft copper wire of 2mm² or larger (AWG14)
Grounding extension: max. 20m

(3) Connection of relay output

When connecting inductive loads (such as relays) to the relay outputs (No. 10-15) on the rear panel, use a protection circuit to keep back electromotive force low and prevent damage to the relay contacts.

Relay output connection.bmp (133016 bytes)

The guidelines for c and r are

c: 0.5 to 1 μF for a contact current of 1 A
r: 0.5 to 1Ω for a contact voltage of 1V

However, this is not always the case due to variations in load characteristics and relay performance.
Please confirm in your experiment that c is responsible for suppressing discharge when the contact is opened, and r is responsible for limiting the current when the contact is closed again. Use a capacitor with a voltage rating of 100V to 300V for c. Use an AC capacitor (non-polarized) in AC circuits. If the load is a relay or solenoid, the recovery time will be delayed.

(4) Connection of external devices

When inputting comparator gate signals, hold signals, and reset signals from external devices, connect the signals to the terminal block on the rear panel.
<See attached document for input circuit and timing chart details>

(5) Installation of terminal block cover (optional)

Terminal block covers (DG0420 type) are available.

(6) Connecting the GS sensor and BCD signal cable

Connect as shown in the diagram below. A signal cable for the BCD connector, type AA8107 (3m long, open on one end), is available as an option.

BCD output connection.bmp (113920 bytes)

Last updated: 2000-12-08