DPF75 Frequency Input Ratemeter/Totalizer, 6 Digits Display

Supported Applications

The Omega DPF70 series comprises 1/8 DIN ratemeters, totalizers, and batch controllers designed for frequency inputs. The product family includes the DPF75 (ratemeter and batch controller), DPF76 (scalable totalizer/batch controller with relays for 2-stage batch control), and DPF78 (scalable ratemeter). These units are engineered to accept pulse signals from sensors such as turbines, paddlewheels, or encoders. The series supports counting up/down modes and quadrature inputs for position or length measurement applications.

Operating Conditions & Performance

The DPF70 series operates within an ambient temperature range of 32 to 129°F (0 to 54°C) with storage capability from -40 to 199°F (-40 to 93°C). The front panel carries a NEMA 4X (IP66) enclosure rating. Measurement accuracy is specified as ±0.1% of reading + 1 LSD for the ratemeter function, which displays accurate to 4½ digits.

Input specifications vary by configuration:

• Pulse Input - Low: 0 to 1 Vdc
• Pulse Input - High: 4 to 30 Vdc
• Low Level Magnetic (Option -LL): 0 to 50 V p-p, accepting 30 mV range signals on Input A.
• Quadrature Inputs: Accepts pulses with a 90° phase shift for direction detection.

The counters can count at speeds up to 10 KHz. The unit features EEPROM memory that stores data for 10 years if power is lost.

Power and Electrical Requirements

• Voltage: 110 VAC ±15% or 220 VAC ±15%; alternatively, 6.5 VA at rated AC voltage.
• Excitation Voltage (Units Only): +12 Vdc @ 50 mA unregulated (-10 to +50%).
• Analog Output Compliance: 3 to 30 VDC non-inductive for the optional analog output.

Configuration Options

The DPF70 series offers configurable outputs, communication interfaces, and input types via specific ordering suffixes. The standard unit includes a 6-digit or 4½-digit display with front-panel programming capabilities.

Ø Analog Output (Option -A): Provides a proportional output of 0 to 20 mA or 4 to 20 mA tracking rate or total. Accuracy is specified as 50uA worst case.
• Serial Communications: RS232 communications (Option -RS232) and RS422 communications (Option -RS422). Up to 99 units can be linked in a loop using standard seven-bit ASCII characters. Note that the "-A", "-RS232", and "-RS422" options are mutually exclusive.
• Low-Level Input: Option -LL enables acceptance of low-level magnetic inputs (30 mV range) for turbine or paddlewheel sensors on Input A. An external amplifier, model FLSC-AMP, is available as an accessory for these applications.

The series provides two control outputs configured as 5 Amp SPST relays. These can be programmed to apply to the "A" total counter, the "A" ratemeter, or the net total of A and B inputs. Presets allow energizing from 0.1 to 99.9 seconds or latching (0.0). The front panel includes a lockout feature using a user-selected 5-digit code.

Key Product Differences

The DPF70 series is differentiated by model number and functional focus:

• DPF75: A ratemeter and batch controller featuring two separate 5 Amp SPST relays for rate alarm or batching.
• DPF76: A scalable totalizer/batch controller with relays designed for 2-stage batch control. It features a 6-digit display.
• DPF78: A scalable ratemeter equipped with two separate 5 Amp SPST alarms and a 4½-digit display.

All models share the same physical dimensions of 1.772 x 3.622 inches (4.5 H x 9.2 cm W) DIN standard, with a depth of 4.06 inches (10.3 cm). The DPF-5 panel punch is available as an accessory for installation.