Large Display Temperature Meters
Instruction Manual
46
Switching Inductive Loads
The relay contacts on the Options PCB are already protected with suppression
components (snubbers).
If additional suppression is required, this suppression can be obtained with RC
networks assembled by the user or purchased as a complete assembly. Refer to
the following circuits for RC network assembly and installation:
AC and DC Loads
Figure 13. AC and DC Loads Protection
Choose R and C as follows:
R: 0.5 to 1
Ω
for each volt across the contacts
C: 0.5 to 1 µF for each 1 A through closed contacts
Notes:
1. Use capacitors rated for 240 VAC.
2. Snubbers may affect load release time of solenoid loads, check to confirm
proper operation.
3. Install the RC network at the Digital Temperature Meter 's relay screw
terminals. An RC network may also be installed across the load, experiment
for best results.
Low Voltage DC Loads
Figure 14. Low Voltage DC Loads Protection
Note
: Use a diode with a reverse breakdown voltage two to three times the circuit
voltage and forward current at least as large as the load current.
4-20 mA Output Operation
The Digital Temperature Meter can be equipped with an isolated 4-20 mA output
option that can be programmed to produce a 4-20 mA signal between any two
temperature values.
