Dwyer Omega – DPG1000ADA-DPG1000DAR AC/DC Powered, Digital Pressure Gauge with Output and Alarms
Product Code: DPG1000ADA
Manufacturer: Dwyer Omega
The DPG1000ADA series is an AC/DC powered digital pressure gauge featuring a precision oil-filled silicon sensor, 4 to 20 mA output, and dual alarms with Hi/Lo normal action control. It delivers ±0.25% accuracy for gauge and absolute pressure ranges and has a fast 100 ms response time, ideal for precise and reliable pressure monitoring.
Normal (Fail-safe) vs. Reverse Action—The convention for alarm action is that with the normal or fail-safe configuration, the alarm output relays will be CLOSED (relay energised) for a clear or non-alarm condition and OPEN (relay not energised) for an alarm condition. This is primarily for users who require an alarm condition if the gauge loses power or suffers a catastrophic failure. In the wiring diagrams, the normally closed and normally open designations refer to standard relay terminology (i.e., the relay contact status with the relay coil not energised). Therefore, with the normal (fail-safe) configuration in a green or non-alarm condition, the relay will be energised so that continuity can be expected between the common and normally open leads. In a red or alarm condition, the relay will be open (not energized) so that continuity can be expected between the common and normally closed leads.
Contact Rating and Protection The contacts of the alarm relays are rated at 1 A/24 Vdc or 0.5 A/ 115 Vac. Switching loads greater than the rating, or switching large inductive loads, will shorten the useful life of the contacts. In low level switching or with dry contacts, the user should consider whether external contact protection, such as snubber networks or arc suppression networks, is required to protect the contacts. In addition, no internal fusing is included in the DPG1000 contact circuits. The circuit external to the gauge alarm outputs should be fused by the user in applications in which good design dictates this practice.
Using the DPG1000DAR Analog Output The analog output is easy to use if a few system considerations are observed. The DPG1000DAR is DC powered, with the gauge power supply (–) tied to the 4 to 20 mA (–). Therefore, the DC supply (–) lead should be considered common with regard to the analog output (–) or ground connection in the user’s system. Be sure to observe the output compliance (voltage drive) capabilities of the gauge. The compliance, and therefore the maximum loop resistance the output can drive, is a function of the supply voltage to the gauge. Consult the manual for maximum loop resistance vs. supply voltage. Too large a loop resistance will cause the gauge output to “limit” or saturate before reaching its full 20 mA output.
