 The 505U radio telemetry module is an economical solution for the remote monitoring of process signals. The 505U can connect to digital, pulse or analogue signals from process transducers, and transmit these signal values by radio. The 505U is suitable for alarm or metering applications, as well as general plant monitoring
Easy to use
The 505U has an internal low power radio transmitter which operates on unlicensed radio channels in the UHF band. A radio licence is not required for the 505U in most countries. The 505U has an operating range of several kilometres. It is suitable for monitoring in utility industries such as electricity, water and gas; and because of its low price, it is also a cost effective solution for short range applications in factories and plants.
Mode of Operation
The 505U transmits the value of the input signal whenever the signal changes, and after a pre-configured time. Each transmission message includes error-checking to confirm the validity of the message. At each transmission, the 505U may be configured to repeat the transmission several times to ensure that the transmission is received correctly. The input signal is then output either as an identical signal or across a serial data link (RS232 or RS485).
Extremely Low Power Consumption
The power consumption of the 505U is very low as it conserves power by reverting to "sleep" mode between measurements of the input signals and transmissions.
The 505U-K can be powered from an external supply, or it can be powered from one or more ELPRO BU-5 battery packs without any other power source. Each battery pack can power the 505U for over a year, depending on input signal configuration. The 505U unit provides an internal alarm on low supply voltage - this alarm can be transmitted by radio.
Weatherproof IP65 Enclosure
The 505U is enclosed in a heavy duty painted aluminium enclosure, weather-proofed to IP66. Signal and power connections to the unit are made via a weatherproof connector.
Compatible with 105U
The 505U is compatible with the 105U range of radio telemetry units*; 105U units may be used to output the process signals, or act as a network master unit to connect to an intelligent host such as a PC or PLC. 105U units may also be used as repeaters to extend radio range - up to five intermediate 105U modules may be used as repeaters in any radio path. More than 10 000 505U units may operate together in a single system. (*Refer to 105U product literature)
Low cost, easy to use and easy to configure
Because of its internal power supply and weatherproof case, the final installed cost of the 505U radio telemetry module is very low, making it a cost effective solution for even simple plant monitoring applications.
Inputs
The 505U-K unit can connect to two discrete or pulse signals and one analogue signal, and will transmit the value of an input when the value changes. The input value is also transmitted if the signal has not changed within a user-configured update time. Pulse signals use the same input connection as discrete inputs.
Alarm and Status Signals
The 505U will connect to digital inputs such as alarm or status signals which are voltage free contacts or TTL signals. Whenever the digital signal changes (off to on, or on to off) the 505U will interrupt its sleep mode and immediately transmit the signal value. For digital inputs, there is a separate update time when the digital signal is active (on). For example, an alarm input may update only every day when it is inactive, but update every minute when it is active. This feature allows a large number of 505U units to share the same radio channel. As well as the external digital inputs, there are two internal digital "inputs" - low battery voltage and analogue setpoint status.
Pulse Signals
The 505U will accept pulse signals up to 10 KHz, suitable for metering applications. Whenever a pulse input is detected, the 505U will interrupt its sleep mode and increase its internal pulse counter. The totalised pulse count is transmitted whenever the count has changed by a pre-configured amount. Transmissions will also occur after the update time. By transmitting the totalised pulse count, the 505U ensures that individual pulses are not lost, Should a radio transmission not be successful, the pulse count is still held in the 505U, and the totalised value will be updated on the next transmission. Change transmissions may be disabled if the pulse rate exceeds a pre-configured amount, to prevent the radio channel becoming congested during peak periods.
Analogue Signals
The 505U has one 0-20 mA (0-10 / 4-20 / 0-20 mA) or 0-10VDC input. The analogue signal may be externally or loop powered - the 505U generates a loop supply voltage. During sleep mode, the loop supply is switched off. After a pre-configured sleep period, the analogue loop supply is activated, and the analogue measurement is taken. A warm-up time may be configured to allow the analogue loop to stabilise before the measurement is taken. If the sleep period is set to zero, then the 505U does not revert to sleep mode, and it will continually measure the analogue signal - note that this is only suitable where the 505U is powered from an external supply. Once the analogue measurement is taken, the 505U will transmit its value if it has changed since the last measurement. A sensitivity value is configured to determine the minimum change to cause a transmission. In addition, the analogue value will be transmitted if the update time has been exceeded.
Configurable setpoint values may be used to generate an internal alarm status which may also be transmitted.
Configuration and Diagnostics
Configuration is easily performed by connecting a PC to an RS232 port on the 505U module. The configuration software which is provided with the unit, also includes dianostic functions. |
