TTL and 24V Converters contain two independent channels.

Press Release Summary:

Model 8501 two-channel 5 to 24 V converter requires 7 mA into 382 ohms per channel to provide 7 mA output into the 3 Kohm, 24 V typical PLC logic input. They may be driven by TTL logic, H series TTL logic, or with open collector NPN transistor. Input frequency is DC to 15 KHz. Model 8502 two-channel 24 to 5 V converter requires 7 mA into 2.5 Kohm per channel to provide 5 mA sinking output to TTL 5 V logic. Input frequency range is DC to 20 KHz.

Original Press Release:

Two Channel TTL to 24V & 24V to TTL Converters

Calex Mfg. Co., Inc. of Concord, California announces the availability of the Models 8501 and 8502. Each Model contains two independent channels which accept a TTL or 24V pulse signal and convert that signal to a 24V pulse or TTL output respectively. The 8501 or 8502 is extremely useful where only one signal type is available. An example would be the direction and step control of a Stepper Motor by Programmable Logic Controller 24 Volt high speed outputs where the motor controller requires 5 Volt logic signal levels. The Model 8501 is a two channel 5V to 24V converter. The two independent channels require 7mA into 382 ohms to provide a 7mA output into the 3K, 24 Volt typical PLC logic input. They may be driven by standard TTL logic, H series TTL logic or with an open collector NPN transistor. Note that low power TTL logic will not drive this unit. The output is a floating optocoupler NPN transistor which may be connected in either source or sink configurations. The input frequency for the 8501 is DC to 15KHz. The Model 8502 is a two channel 24V to 5V converter. Each channel requires 7mA into 2.5K ohms to provide a 5mA sinking output to TTL 5 Volt logic. The output is an optocoupler NPN transistor collector and requires the 5 Volt logic supply and its return. The input frequency range is DC to 20KHz. The inputs are isolated by optocouplers and are protected from ESD by varistors. The two outputs have a common emmiter with each output collector capable of sinking a minimum of 5mA. The 8501 and 8502 are housed in a DIN Rail mount enclosure which measures 1.65 "H x 1.06"W x 3.78"L. Both models are UL 508 and 1604 recognized. All Calex Signal Conditioning products are backed by Calex' s five year warranty. List price for the 8501 and 8502 is $45.00. Units are available from stock. For additional information, contact CALEX Mfg. Co., Inc., 2401 Stanwell Dr., Concord, CA, 94520
web:, email:, ph: 800-542-3355 or 925-687-4411, fax: 925-687-3333.

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